Boxes are commonly used to contain various items for storage and transport, but their three-dimensional structure is inconvenient when the box is empty. Empty boxes can be difficult to store, and treating boxes as disposable (i.e., discarding them after each use) can be uneconomical. Thus, it is desirable to have boxes that can be reusably disassembled from their three-dimensional box configurations for easy storage.
Many boxes are initially assembled from a one-piece slab 20 of material (broadly, a “blank”). Adhesives are commonly used to secure panels of a blank in respective positions to assemble a box structure. Though adhesives may be sufficiently strong to secure some blanks in respective box configurations, they do not permit easy disassembly without damaging the blank.
For improved reusability, some box blanks have used interlocking structural features to secure the panels of the blank in a box configuration. However, these box blanks suffer from various limitations. For example, in some cases the interlocking structural features provide insufficient strength to hold the blank in the box configuration under the strain of the static and dynamic forces of the items contained in the box in use. Likewise, in some cases, the very use of the interlocking structural features causes damage thereto, rendering the blank incapable of reuse after disassembly.
One example of an interlocking structural feature that suffers from these limitations is a dart-type lock. Dart-type locks typically include an opening (e.g., in the side wall of a box) and a corresponding dart tab configured to be lockingly received in the opening. The dart tab typically has a widthwise span that is slightly wider than the width of the opening. The widthwise span of a typical dart tab is oriented substantially orthogonal to the longitudinal axis of the dart panel. As the name suggests, the front edge of a dart tab is tapered to a point. A force is applied generally in the direction of the longitudinal axis of the dart tab to insert the dart tab into the opening. As the front edge (i.e., the point) of the dart tab is inserted further into the opening the widthwise span is increasingly compressed by the constraints of the narrower opening. Though the dart tab may show some widthwise resilience once it is received in the opening (e.g., the widthwise span may return to a width wider than that of the opening), the act of insertion tends to damage the dart tab. Likewise, the act of pulling the dart tab out of the opening tends to inflict additional damage to the dart tab. The damage inflicted by inserting and removing the dart tab through the opening can permanently deform the dart tab such that its widthwise span becomes permanently narrower than the width of the opening. When this occurs, the dart-type lock becomes inoperable. As a result, dart-type locks are not well-suited for frequent reuse as an interlocking structure.
Accordingly, a box blank with improved reusability is desired.